package com.ql.cloud.commons.base.component;



import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;


/**
 * springContext
 * 
 * @author 齐龙
 * @time 2016-07-18
 */
@Component
@Lazy(value = false)
public class SpringContextHolder implements ApplicationContextAware {
    private static ApplicationContext applicationContext;

    private static Logger logger = LoggerFactory.getLogger(SpringContextHolder.class);

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        SpringContextHolder.applicationContext = applicationContext; // NOSONAR
    }


    /**
     * 清除SpringContextHolder中的ApplicationContext为Null.
     */
    public static void clearHolder() {
        logger.debug("清除SpringContextHolder中的ApplicationContext:" + applicationContext);
        applicationContext = null;
    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        checkApplicationContext();
        return applicationContext;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        checkApplicationContext();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. 如果有多个Bean符合Class, 取出第一个.
     */
    public static <T> T getBean(Class<T> requiredType) {
        checkApplicationContext();
        return applicationContext.getBean(requiredType);
    }

    /**
     * 清除applicationContext静态变量.
     */
    public static void cleanApplicationContext() {
        applicationContext = null;
    }

    private static void checkApplicationContext() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext未注入,请检查SpringContextHolder配置");
        }
    }

//    @Override
//    public void destroy() throws Exception {
//        SpringContextHolder.clearHolder();
//    }
}
